The purpose of the present study is to analyze an unique body of data related to zinc metabolism in normal healthy men and women of various ages. THe study was a carefully controlled investigation of 75 normal subjects, 44 men, 31 women, aged 18-84 yr. Each was given 10 MuCi carrier free 65ZnCl2 orally and gastrointestinal absorption, tissue distribution and excretion of the isotope evaluated by whole body counting, partial body counting over liver and thigh and by activity in whole blood, serum, red blood cells, urine and stool at regular intervals over 8-9 months. At this time subjects were given 10 mg oral zinc ion daily and all measurements noted above repeated at regular intervals for an additional 8-9 months. Using traditional analytical techniques zinc absorption for the entire group was 65 (plus/minus) 11% (mean (plus/minus) 1 SD). However, comparison of absorption by sex with age demonstrated that women had significantly increased absorption over men but with age excluded, sex differences were not significant. With all subjects considered, absorption decreased significantly in a linear manner with age. To analyze these data adquately we propose to apply innovative techniques, compartmental analysis and application of results obtained to a recently developed integrated model of zinc metabolism. The model represents a composite of zinc metabolism formulated from the studies of patients given 69mZn and 65Zn. This model, developed in our laboratory over the past seven years, represents a comprehensive approach to the study of zinc metabolism from studies performed in a manner similar to that noted for normal subjects. With these innovative techniques it was possible to determine the kinetics of zinc absorption and gastrointestinal resecretion, tissue zinc distribution and kinetics of zinc movement into and out of tissues as well as parameters of zinc excretion. Because of the uniqueness of the present data in normal men and women of various ages and because of the power of these new innovative techniques their application will allow systematic analysis of tissue zinc masses, rate constants into and out of body compartments and daily requirements for zinc for age and sex. Without these analytical techniques it is not possible to obtain these detailed results. The purpose of this application is to obtain the assistance of a scientist familiar with the use of these innovative analytical techniques to develop this comprehensive composite of zinc metabolism in aging men and women.